Machine for automatically varnishing electrical resistors



Jan. 25, 1955 Filed May 5, 1952 V. A. WOODELL ET AL MACHINE FORAUTOMATICALLY VARN ELECTRICAL RESISTORS ISHING 2 Sheets-Sheet l IN VENTOR5.

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Pda/ I? Hanan 0y v. A. woom-zu. EIAL 2,700,368 MACHINE FOR AUTGMATICALLYVARNISHING Y ELECTRICAL RESISTORS 2 Sheets-Sheet 2 Jan.25, 1955 FiledMay 5, 1952 [FET- I. M I 0 a/dz g l I .WAZZZl/i/l/ V/l/A United StatesPatent MACHINE FOR AUTOMATICALLY VARNISHING ELECTRICAL RESISTORS VictorA. Woodell, Atehison, Kans., and Paul R. Hannaway, Independence, Mo.,assignors to Electra Manufacturing Company, Kansas City, Mo., acorporation of Missouri Application May 5, 1952, Serial No. 286,048

Claims. (Cl. 118-316) This invention relates to the manufacture ofrelatively small articles and has to do primarily with a machine forautomatically coating the articles with a fluid, thereby eliminating thenecessity of a large number of workmen and assuring an even distributionof the coating substances on each of the articles themselves. I

More particularly, the invention hereof relates to the manufacture ofelectrical resistors. As one of the necessary steps in the production ofelectrical appliances of this character, each resistor must be varnishedto completely cover the outer surfaces thereof rather evenly.

It is accordingly the most important object of the present invention toprovide an automatic machine for feeding the resistors singly to acoating station wherein the resistor is sprayed with a suitable varnish,and thereupon removed from the spraying station and deposited upon aconveyor for advancing the same away from the coating station.

Another object hereof is to provide means for continually andsuccessively depositing a number of resistors singly upon a supportwithin a varnish spraying station coupled with means capable ofreceiving the resistors singly and removing the same from the sprayingstation before successive resistors are deposited within the stream ofsprayed liquid.

Other objects hereof include the way in which means in provided forautomatically pumping a varnishing fluid and directing the same againstthe resistor while it rests within the spraying station; the way inwhich the varnish is permitted to drain from each resistor and thedroplets removed; the way in which a specially formed endless conveyoris provided to receive the resistors and advance the same to successiveconveying means; and many more minor objects, all of which will be madeclear as the following specification progresses.

In the drawing:

Figure l is a top plan view of the machine for automatically varnishingelectrical resistors made in accordance with the present invention.

Fig. 2 is a side elevational view thereof.

Fig. 3 is an enlarged, fragmentary, vertical, crosssectional view takensubstantially through the longitudinal axis of the conveyor.

Fig. 4 is a fragmentary, cross-sectional view taken on irregular lineIV-IV of Fig. 3.

Fig. 5 is an enlarged, detailed, cross-sectional view taken on line V-Vof Fig. 3; and

Fig. 6 is an enlarged, detailed, cross-sectional view taken on line VIVIof Fig. 3.

Electrical resistors 10, to be coated or varnished through utilizationof the automatic machine about to be described, are illustrated in Figs.3 to 6 inclusive of the drawings. Resistors 10 are each provided with apair of opposed leads or pigtail wires 12 at the ends thereof, whichwires are to be maintained free of the varnishing substance, although itis of no consequence if a short length thereof adjacent the resistoritself, receives some of the coating substances. i

Apparatus not herein shown and forming no part of the present invention,is provided to automatically and continuously feed or advance theresistors 10 to the varnishing machine of this invention, and forpurposes of illustration, a small chute or platform 14 is shown having aplurality of resistors 10 thereon for movement toward the feedingportion of the present machine herein broadly designated by the numeral16.

Feeder 16 is rotatably mounted within a pair of upice standing legs 18and 20 of a frame 22 having a bight or lowermost wall 24. Feeder 16includes a pair of spacedapart, preferably circular, flat discs 26coaxially mounted on a common shaft 28 and held in spaced-apartrelationship by means of a collar 30 on the shaft 28. As aforementioned,the shaft 28 spans the distance between the legs 18 and 20 of frame 22within which it is rotatably mounted, and holds the feeder 16substantially midway between the legs 18 and 20 as illustrated in Fig. 1of the drawings.

The two discs 26-26 of the feeder 16, are each provided with a pluralityof notches 32 having inclined trailing portions 34, feeder 16 normallytraveling as indicated by the arrow in Figs. 2 and 3. The length of thecollar or spacer 30 and, accordingly the distance between the discs26-26, is slightly greater than the over-all length of the resistors 10as shown in Figs. 4 and 5 of the drawings.

The feeder 16 chosen for illustration is provided with four equallyspaced notches 32 and there is associated with each notch 32 of eachdisc 26 on the outer faces of the latter, a substantially L-shaped dog36 swingably secured to its disc 26 by means of a pivot pin 38. One ofthe legs of the dog 36 is provided with a small notch or indentation 40and the dogs are so balanced as to maintain substantially the positionshown in Figs. 2 and 3 of the drawnigs wherein the longitudinal axis ofthe other leg thereof is vertical. Thus, the dogs 36 move into and outof partial overlapping relationship with the notches 32 as the feeder 16rotates for reasons hereinafter to be made clear.

A device which may be termed for the present purposes a remover, isbroadly designated by the numeral 42, and is similar to the feeder 16 inthat the same comprises a pair of spaced, parallel, substantiallycircular discs 44. The distance between the discs 4444 is slightlygreater than the distance between the discs 26-26 and such spacing ismaintained by a collar 46 between the discs 44-44 and mounted on a shaft48. Shaft 48 is likewise rotatably carried by the legs 18-20 of frame 22for rotation on an axis parallel with and in the same horizontal planeas the axis of rotation of shaft 28.

Feeder 16 and remover 42 are in side-by-side relationship and the latteris adapted to receive the resistors 10 and particularly the wires 12-12thereof by virtue of notches 50 in each disc 4444 respectively and equalin number to the notches 32. A triangular-shaped extension or ear 52extending outwardly from the periphery of each disc 4444, is disposedadjacent and in trailing relationship to each notch 50 respectively.

A coating station 54 in the nature of an upstanding, polygonal tubehaving the upper and lowermost ends thereof open, is disposed betweenthe feeder 16 and the remover 42. The tubular coating station 54 has apair of opposed, vertical side walls 56-56 disposed between the discs2626 and accordingly, disc 44-44 as shown in Fig. 4 of the drawings,each wall 56-56 having a V-shaped notch 58 at the uppermost end thereofterminating at the apex thereof in a vertical slot 60.

A pin 62 shown most clearly in Fig. 5, joins the walls 56-56 immediatelybelow the slots -60. The tubular coating station 54 extends through anopening 64 in the bottom wall 24 of the frame 22 communicating with acontainer 66 for varnish or other coating substance 68, the container 66having a fill-plug 70. The container 66 has a pump assembly 72 therein,the piston whereof is in turn provided with an upstanding, spring-loadedstem 74. A pair of conduits 76 communicating with the housing of pump 72extend upwardly into the tubular station 54, each terminating in aperforated manifold 78 adjacent the slots 60. Thus the conduits 76 aresubstantially T-shaped and the perforations of the manifolds 78 aredisposed to direct the fluid 68 in the form of a spray against aresistor 10 when the same is within the coating station 54 asillustrated in Figs. 3 and 4.

A conveyor 80 extending between the discs 44 of remover 42, is ofendless nature and trained about a pair of spaced sprocket wheels 82 and84, the former of which is in turn carried by a shaft 86 within thehorizontal plane of shafts 28 and 48 and rotatably carried by the walls18 and 20. The sprocket wheel 84 is mounted on a shaft 88 that is inturn supported by a pair of uprights 90. Shaft 88 is likewise providedwith a pair of sprocket wheels 92, each carrying an endless conveyor 94,the conveyors 2d obviously passing over additional sprocket wheels notshown and spaced from the shaft 38.

Conveyor 80 is in the nature of a chain having a plurality of links 96joined by pivot pins and each provided with a pair of substantiallyZ-shaped brackets )8, see Fig. 6, having notches 1%. The legs of thebrackets 98 having notches 100 therein, are joined by a crosspin 102immediately below the notches 111 0. Guide means to assure transfer ofresistors 16 from the conveyor 80 to the conveyors 94 includes a pair ofrods 1% between the conveyors 94 and inclined downwardly from a pointadjacent the conveyor 86 as shown in Figs. 1 and 2. The guide rods 1%embrace the brackets 98 and terminate at the uppermost ends thereofimmediately below notches 100 as the same successively pass the rods194, it being understood that the conveyor 80 travels in the directionof the arrow of Fig. 2.

A common means not shown, may be provided to advance the conveyors 3tand 94 in the same direction and rotate the feeder 16 and remover 42 inthe same direction. Assuming that a prime mover is coupled with theshaft 88, rotation of the latter will rotate the sprocket Wheels 84 and92. As the conveyor 84) drives sprocket wheel '32 and accordingly theshaft 86, the remover 42 will be rotated by virtue of a train of gears106 joining the shafts 86 and 48. Feeder 16 is rotated by means of atrain of gears 1% interconnecting the shafts 23 and 48.

The pump of assembly 72 is actuated by means of a piston not shown,within a cylinder 11E carried by the wall above the spring-loaded stem74. The piston within cylinder 110 has a vertically reciprocable plunger112 depending therefrom in alignment with the stem '74, and such pistonis adapted to be driven by compressed air directed to the cylinder 110by means of a hose 114. A second hose 116 is connected with a source ofcompressed air not shown, and both hoses 114116 are joined with valvingmeans 118.

Valve 118 is operated by an electrical solenoid 120 having connectionwith the valving means 118 by means of its reciprocable core 122. Anelectrical switch 124 for closing a circuit through the solenoid 120 hasits spring-like actuating arm within the path of travel of a multiplecam 126 that is secured to the shaft 48 for rotation thereby. The partsare shown in Fig. 2 of the drawings with cam 126 closing switch 124,thereby energizing the solenoid 120, opening the valving means 118 andsupplying compressed air to the cylinder 110. This forces the plunger1'12 downwardly to actuate the stem 74 and thereby pump fluid from thecontainer 66 upwardly through the conduits 76 and thence from the sprayheads or manifolds 78.

A drip pan :128 in the nature of a sump, is disposed in underlyingrelationship to the conveyor 80.

During operation by virtue of a common prime mover coupled with theshaft 83, the conveyors 8t) and '94 operate continuously and the feeder16, the remover 42 and the cam 126, rotate continuously. With theresistors 10 available on the chute 14 at all times to the feeder 16, assoon as a notch 32 moves to a position adjacent the chute 14, a resistor10 will move into position between the discs 26 as shown in Figs. 3 and4. In other words, the opposed wires 12 of resistors 10, bear againstthe peripheries of discs 26 and notwithstanding the inclined portions 34of the notches 32, a resistor 10 will be maintained in a notch 32 byoperation of the associated dog 36. The indentation 40 of dogs 36underlie each of the wires 12 until the feeder 16 moves the resistor 10toward the uppermost end of its path of travel.

As shown in Fig. 3 of the drawings, the dogs 36 automatically swing awayfrom the corresponding notches 32 and a resistor 10 therein afterleaving the chute 14. Resistor 10 is carried downwardly toward thestation 54 and as soon as the wires 12 come :into contact with theproximal inclined edges of notches 58, resistor 10 will be pulled orforced from the opposed notches 32 of discs 26 and the wires 12 willultimately'fall into the slots 60. It is noted that the resistor 10itself is always disposed between the discs '26 and thence between thewalls 56.

.Almost simultaneously with the dropping of a resistor 16 4 pressed airto the cylinder 110. Pump 72 will furnish a supply of liquid to theconduits 76 and the resistor will be sprayed with a coating of varnishor the like 68.

It is noted that the four notches 50 of the remover 42 are offsetslightly with respect to the notches 32 of feeder 16. Accordingly, justbefore another resistor 10 is fed to the station 54 by the feeder 16,the remover 42 will receive the varnished resistor 19 and carry the sameupwardly and laterally to the conveyor 80. The projections 52 move intounderlying relationship to the wires 12, whereupon the latter move intothe notches 50. As the varnished resistor approaches the conveyor 80,they will be forced into notches 10b of one of the pairs of brackets 98,conveyor 80 thereupon carrying the resistors 10 as shown in Fig. 3toward the conveyors 94. As the resistor approaches the guides 124-, thewires 12 will come into contact with the upper ends of rods 104 and bestripped from the notches for deposit upon the conveyors 94. An evencoating of varnish is assured by virtue of the fact that the same isfree to drip therefrom, not only in the station 54, but as the resistors10 are advanced .by conveyors 8t and .94.

Normally, one or more small droplets collect along the lowermost edge ofthe resistors 15 these droplets being removed by the pin 62 and by theseries of pins 102. All excess liquid within the liquid station 54gravitates to the container 66 and the drippings from the conveyor 80are collected by the sump 128.

By virtue of the plurality of spaced-apart pairs of brackets 98, and byvirtue of the particular nature of the remover 42, the resistors 16 areheld spaced-apart a sufiicient length of time to avoid disturbance ofthe varn-ish thereon until the latter has dried to a point whereinterengagement between the resistors will produce no adverse effect.After the resistors 11 are deposited on a conveyor 94, a slightinterengagement therebetween will not effect the resistances of thecoated electrical elements since the varnish will have become partiallydried. It is contemplated that the conveyors 94 be relatively long so asto lengthen the drying time and, in this connection, it may be advisableto provide a series of conveyors to successively receive the resistorsby means of the wires 12 thereof until the same are sufficiently dry topermit further handling.

It .is :now seen that the machine hereof is entirely auto matic,requiring no operator attention whatsoever, and that the resistorsthemselves are not handled nor engaged so as to prevent an even coatingof the varnish thereon. This particular operation in the manufacture ofelectrical elements of this kind, can thus be speeded up tremendouslyand a more perfect coating thereby produced.

These factors are extremely important in precision articles of thisnature wherein resistance values must be maintained within close limitsand, while the machine hereof may be used for coating many differingtypes of articles .of manufacture, other resistors or other electricalelements, such changes and modifications as fairly come within thespirit of the invention as defined by the scope of the appended claims,are contemplated hereby.

Having thus described the invention what is claimed as new and desiredto be secured by Letters Patent is:

1. In an article coating machine, article feeding apparatus including arotatable element having a number of article-receiving means thereon; acoating station having an article support disposed to receive an articleas the same gravitates from said means; structure for forcing a coatingsubstance against the articles While the same is resting .on saidsupport; and means for successively lifting said articles-singly fromthe support and thereupon removing the s'am'efrom the station after thearticles have been coated with said substance and prior to deposit of asuccessive article on the support, said last mentioned means including asecond .rotata'ble element having a plurality of article-receiving meansthereon.

.2. A machine for varnishing electrical resistors of the kind having apair of opposed wires, said machine comprising a rotatable feederprovided with a number of resistor-receiving means adapted to dischargeresistors therefrom by .force of gravity .as the feeder is rotated; avarnishing station having a resistor support disposed to'receive asingle resistoras it gravitates from the feeder; means for-directingvarnish to the resist-or while thesame is :on the support; a rotatablerem-over provided with .a number of resistor-receiving means for liftingthe varnished resistor tfrom said support and :advancing the same awayfrom the station, said resistor-receiving means for the feeder and forthe remover each comprising wirereceiving openings formed in the feederand in the remover respectively, said feeder and said remover eachhaving a pair of discs spaced to receive the resistors therebetween,said openings consisting of notches formed in the discs; means forrotating the feeder and the remover in synchronism.

3. A machine for varnishing electrical resistors of the kind having apair of oppositely extending wires, said machine comprising a feeder anda remover mounted for rotation in the same direction and each includinga pair of discs, spaced to receive resistors therebetween, there being anumber of notches in the discs adapted to receive said wires of theresistors; a varnishing station having a resistor support includingwire-receiving notches disposed Within the path of travel of the wiresas the feeder is rotated to strip the resistors successively from thefeeder; means for driving the feeder and the remover to successivelydeposit resistors on said support and remove the same, said supportbeing disposed to hold the resistor thereon Within the path of travel ofthe remover whereby the latter strips the resistors from the support;and means for forcing varnish against the resistors While the same areon the support.

4. A machine for varnishing electrical resistors of the kind having apair of oppositely extending wires, said machine comprising a feeder anda remover mounted for rotation in the same direction and each includinga pair of discs, spaced to receive resistors therebetween, there being anumber of notches in the discs adapted to receive said wires of theresistors; a varnishing station having a resistor support includingwire-receiving notches within the path of travel of the wires as thefeeder is rotated; means for driving the feeder and the remover tosuccessively deposit resistors on said support and remove the same; andmeans for forcing varnish against the resistors while the same are onthe support, said station being embraced by the feeder and the remover.

5. A machine for varnishing electrical resistors of the kind having apair of oppositely extending Wires, said machine comprising a feeder anda remover mounted for rotation in the same direction and each includinga pair of discs, spaced to receive resistors therebetween, there 'beinga number of notches in the discs adapted to receive said wires of theresistors; a varnishing station having a resistor support includingwire-receiving notches within the path of travel of the wires as thefeeder is rotated; means for driving the feeder and the remover tosuccessively deposit resistors on said support and remove the same; andmeans for forcing varnish against the resistors while the same are onthe support, said station being embraced by the feeder and the remover,and the discs of the feeder and the remover being in substantiallyedge-t0- edge relationship.

References Cited in the file of this patent UNITED STATES PATENTS1,030,636 Beadle June 25, 1912 1,062,001 Hall May 20, 1913 1,382,149Walker June 21, 1921 1,700,697 Draper Jan. 29, 1929 1,874,568 Melvilleet a1 Aug. 30, 1932 2,283,615 Skinner et al May 19, 1942 2,363,487Anderson Nov. 28, 1944

